Sum between array's elements and creation of new array in Cypher language

Question

I need to sum an element of an array with the element before and create a new array with this elements. In manual way now I am using this code:

match (a:User) 
with collect(a.capital) as cap 
with cap as cap, length(cap) as len
return cap[0], 
       cap[0]+cap[1], 
       cap[0]+cap[1]+cap[2],
       cap[0]+cap[1]+cap[2]+cap[3], 
       cap[0]+cap[1]+cap[2]+cap[3]+cap[4], 
       cap[0]+cap[1]+cap[2]+cap[3]+cap[4]+cap[5], 
       cap[0]+cap[1]+cap[2]+cap[3]+cap[4]+cap[5]+cap[6], 
       len

But I need to use a query Cypher that do this operation on arrays with different lengths.

Answer 1

Cypher has the reduce function :

WITH [12,28,74,45] AS cap
RETURN reduce(x = 0, v IN cap | x + v)
// 159

You can also make use of APOC collection functions :

WITH [12,28,74,45] AS cap
RETURN apoc.coll.sum(cap)
// 159.0

update

WITH [12,28,74,45] AS cap
UNWIND range(1, size(cap)) AS i
WITH apoc.coll.sum(cap[0..i-1])
     + apoc.coll.sum(cap[0..i]) AS sum
RETURN collect(sum)

Result :

╒═══════════════════════╕
│"collect(sum)"         │
╞═══════════════════════╡
│[12.0,52.0,154.0,273.0]│
└───────────────────────┘

Answer 2

Thank you I tried in this way on my DB and it's working:

   WITH [12,28,74,45] AS cap
   UNWIND range(1, size(cap)) AS i
   WITH apoc.coll.sum(cap[0..i]) AS sum
   RETURN collect(sum)